Question

xplain the various chemical phenomena and reaction kinetics Arrange the following in order of increasing acidities giving reasons HCI, H2SO4, HCIO4, CH3COOH, H2CO, CIC COOH
Completely solved this question
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Answer 1

(i) I

2

<F

2

<Br

2

<Cl

2

The electron affinity of Chlorine is maximum in the periodic table and so the bond dissociation enthalpy. Flourine has lower bond dissociation enthalpy than Br

2

and Cl

2

. Due to small size electronic repulsion is very high. I

2

has lowest bond dissociation enthalpy due to quite larger size it is easiest to break the bond.

(ii) HF<HCl<HBr<HI⇒Acidic strength of Halogen acids increases down the group.

(iii) BiH

3

<SbH

3

<AsH

3

<PH

3

<NH

3

⇒ Basic strength decreases down the group because as we go down the group the size of the atom and thus the electron density decreases. These compounds are lewis base having 1 lone pair on the central atoms. As the electron density decrease the tendency to donate electron pair decreases.